(a) Field of the Invention
The present invention relates to liquid crystal displays and manufacturing methods thereof, more specifically to liquid crystal displays having electrode arrays for applying electric fields parallel to substrates and thin film transistors as switching elements and manufacturing methods thereof.
(b) Description of the Related Art
A liquid crystal display (LCD) having an electrode array for ganerating an electric field which is parallel to substrates (IPS mode; in-plane switching mode) is disclosed in U.S. Pat. No. 5,598,285 of Kondo et al.
The IPS mode LCD of Kondo et al. has two substrates opposite each other and a liquid crystal layer therebetween. Two kinds of electrodes for generating electric field, common electrodes and pixel electrodes are formed on one of the substrates. An alignment layer is coated on the electrodes.
However, since the two kinds of electrodes are made of different layers and have different thickness, the surface of the alignment layer may not be flat, and this causes non-uniform rubbing which may result in light leakage.
Moreover, the liquid crystal display of Kondo et al., in particular, transistors of the liquid crystal display are easily defected by the electrostatic discharge because the two electrodes are formed together on a single substrate.
For electrostatic discharge protection, all wires may be short-circuited during the manufacturing process and separated after the manufacture of the panel is completed. However, this method is complicated.